Newbie needs help

Hello everybody
i am complete newbie to this big trading world and i so happy to have found such a community to help me start in this business.
i have been practicing for a while on a DEMO and i think i am ready now to start live trading but since i have never opened an account with a real broker before, i dont have any clue on how to deal with that.
During my demo practice i been really satisfied and comfortable using NINJA trader platform and i would like to use it in realtime trading so i checked the list of the brokers that support it http://www.ninjatrader.com/webnew/partners_onlinetrading_brokers.htm

i personally narrowed it down to MIRUS FUTURES, IB, ADVANCED, and MAN FINANCIAL........what is your opinion on which one to go with.. my requirements in a broker is REALLY FAST execution as i only scalp, reliable desk support when things go wrong, and minimal filling errors and that sort of problems

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My concern is what are the risks of wiring and putting your money in any of the brokers mentioned. i know this is a silly question but, i only have very limited money to invest in this business and i cant afford to loose my money to a broker scam or other reason as such ( i can afford though to loose in actual trading coz then it would at least have been educational to me to learn from my mistakes).. so back to the point...
i mean with mirus futures it is a small private company with a not so impressive encouraging site.

- what guarantees are there to protect me against ways that would lead to loosing my money to sth other than actual trading

- what happens to my money should the firm go bankrupt, or other financial crises or legal ones

- i plan to open the account via the internet, i learned that during that i send all the require info to them and they just send you pass but NO hard paper documentation to hold them responsible of the money i wired .(again i know its a silly question but an important one to a complete newbie like me)

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since i have no experience with brokers i hope that you ,experienced traders, to put a list here of all the things that go wrong with an online broker and how to avoid them, correct them or just bewared of them...this i think would be a GREAT help for prospective traders and complete newbies like me..

i read here on the forum things like late filling, being charged falsely, enter a trade u didn't do, ...ect ..

what else and most important HOW DO ONE CHECK UP AFTER A BROKER FOR ERRORS AND SCREWUPS...

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FInally , i tend towards MIRUS FUTURES as they offer NJ with ZEN FIRE, which i heard would be good for my scalping need of fast execution and for the fact that most of my demo was on NJ ZF
but i would like to know
what are the risks of opening with MIRUS being the small private firm it is and what guarantees are there for my money (of course anything but loss in actual trades!!!)
i would like the opinion of people with experience, recent or current one, with MIRUS

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thanks i know it has been a long post but i hope it would be a place for all info newbies need in all fields (as its categorized by sub forums) to be gathered here